We are currently in an El Niño year, when a band of warm water develops in the tropical Pacific. El Niño is a natural event that occurs every few years and has an impact on global weather.
There’s an 80 percent chance it will persist into next spring, and a greater than 90 percent chance of it lasting through this upcoming winter, according to a July report from the National Oceanic Atmospheric Administration. This may be the strongest El Niño since 1997-98, so look for out of the ordinary weather conditions.
Although our summers are more agreeable than in many other locales, the US is among the hotter nations in the world, mainly due to its southwestern desert. In Death Valley, California, temperatures routinely break 100 degrees—far higher than desert regions in the Middle East, Australia, and North Africa (although on September 13, 1922, Al Aziziyah, Libya, had the highest temperature ever recorded anywhere of 136).
With heat comes drought. Between 1933 and 1938, the Great Plains were afflicted with the “Dust Bowl” period of drought and heat, when windstorms blew the topsoil into dust clouds capable of turning day into night.
At its worst, the drought covered over 50 million acres from Texas to Canada, and from Colorado to Illinois. One 1935 dust storm in the Texas panhandle lasted nearly 38 days (or 908 hours). Some of the individual storms persisted for three consecutive days.
The weather in our hemisphere moves predominately west to east, so the dust storms were carried towards the Eastern Seaboard. Dust deposits were reported on ships as far as 300 miles out into the Atlantic.
The Palmer Drought Severity Index was designed by the US Weather Bureau to measure moisture in the soil. A reading of positive four or greater indicates extremely moist soil; negative four or less, extremely dry soil. Normal moisture content is between -1.9 and 1.9. During the Dust Bowl years, the Palmer Index dropped well below five in the Great Plains, even approaching -9.0 in 1934.
A more rare heat-related phenomenon is the heat burst, or heat flashes, characterized by a sudden spike in air temperature lasting more than a few minutes. They are usually in close proximity to thunderstorms and most common at night, when the relatively cooler air contrasts strongly with a sudden burst of hot air.
In the February 1994 issue of Monthly Weather Review, Colorado State University researchers Ben Bernstein and Richard Johnson reported their findings on heat bursts, as follows:
The heat burst, near the remnants of a thunderstorm cluster, is a downburst of air from the thunderstorm displacing a shallow pool of cool air hugging the ground. The phenomenon is akin to what would happen if one blew strongly down onto a shallow puddle of water; the puff from your lungs temporarily clears water from a spot on the surface.
Heat bursts are extreme. In June 1967, a brief temperature of 188 degrees in the shade was reported at Abadan, Iran, causing dozens of fatalities and liquefying asphalt. However, this report had no corroborating information on the event, leaving doubt about its authenticity.
Closer to home, on July 10, 1879, the Minneapolis Tribune published the following:
A blast of hot air passed from south to north through portions of New Ulm and Renville County last Sunday evening. It lasted only a minute or two, but so intense was the heat that people rushed out of their houses believing them to be on fire.
On December 17, 2003, the National Weather Service accidentally predicted imminent doom due to a heat event. A test message erroneously posted on the agency’s website during a training session read:
Unusually hot weather has entered the region for December as the Earth has left its orbit and is hurtling towards the sun. Unusually hot weather will occur for at least the next several days as the Earth draws ever nearer to the sun.
By midafternoon, the statement had been removed and replaced by a correction.
No doomsday is in store for us as summer draws to a close. The rest of August should be warmer than average earlier on, then leveling off with showers and thunderstorms. September, and even October, could see above average temperatures and rainfall as well.